In telecommunications, error correction encoding methods (also called Forward Error Correction (FEC)) are used to protect so-called source data to be transmitted, from errors that will come from the transmission. To do this, redundancy is added to the source data in order to enable the recipient to detect and correct part of the errors.
The error correction encoding is followed with a modulation for transmission, that is why generally, the modulation and coding scheme (MCS) is used to designate both the error correction encoding and the modulation.
In prior art is known an error correction encoding method commonly called “turbo code”. This is an error correction encoding method, implementing in parallel at least two independent steps of systematic convolutive encoding of all the data to be encoded, and at least one time interleaving step changing the order for taking into account data for each of the encoding steps. Turbo codes are for example presented in French patent FR2675971. The decoding implements an iterative decoding algorithm based on the Bahl, Cocke, Jelinek and Raviv algorithm and an a posteriori maximum search.
One drawback of turbo codes however is that all the source data are equally protected.
UEP (Unequal Error Protection) codes, born with GSM technology, bring a response to this drawback by enabling digital data of a frame to be gathered into different classes depending on their importance, and each class to be protected depending on its priority level (a priority level all higher is assigned as the datum is important).
This principle enables transmission resources as well as the frequency band width used to be optimized.
A known drawback of UEP codes is that each class is separately processed. The different classes are first separated, and then separately encoded. The encoded data of each class are then separately modulated. After transmission, the data of a same frame are thus decorrelated. This involves a resource loss because there is for example a need for:                further headers (that is further data used for defining a data packet, for example the data of a class in the case where the different classes are independently processed), and        further processings to resynchronize the data from different classes of a same frame after transmission.        
Further, this resynchronization steps generate reception delays.
Such a resource loss goes against the current demand for a higher transmission rate, higher network capacity and shorter transmission delay.